Trivial fix: change launch to gstreamer-launch in README.
Trivial fix: change launch to gstreamer-launch in README.

Original commit message from CVS:
Trivial fix: change launch to gstreamer-launch in README.

ahmedammar/platform_external_gst_gstreamer,lovebug356/gstreamer,shelsonjava/gstreamer,jpakkane/gstreamer,ylatuya/gstreamer,collects/gstreamer,lovebug356/gstreamer,lubosz/gstreamer,Distrotech/gstreamer,surround-io/gstreamer,drothlis/gstreamer,cablelabs/gstreamer,drothlis/gstreamer,jpxiong/gstreamer,Lachann/gstreamer,ensonic/gstreamer,mparis/gstreamer,lovebug356/gstreamer,lubosz/gstreamer,StreamUtils/gstreamer,ahmedammar/platform_external_gst_gstreamer,StreamUtils/gstreamer,krichter722/gstreamer,ensonic/gstreamer,ahmedammar/platform_external_gst_gstreamer,Lachann/gstreamer,lovebug356/gstreamer,justinjoy/gstreamer,centricular/gstreamer,drothlis/gstreamer,surround-io/gstreamer,krichter722/gstreamer,Distrotech/gstreamer,cablelabs/gstreamer,krieger-od/gstreamer,cfoch/gstreamer,cfoch/gstreamer,mrchapp/gstreamer,ensonic/gstreamer,krichter722/gstreamer,krieger-od/gstreamer,lovebug356/gstreamer,cablelabs/gstreamer,lubosz/gstreamer,justinjoy/gstreamer,jpakkane/gstreamer,magcius/gstreamer,mparis/gstreamer,jpxiong/gstreamer,cfoch/gstreamer,krichter722/gstreamer,justinjoy/gstreamer,collects/gstreamer,Distrotech/gstreamer,lubosz/gstreamer,centricular/gstreamer,krieger-od/gstreamer,StreamUtils/gstreamer,Lachann/gstreamer,mrchapp/gstreamer,justinjoy/gstreamer,jpxiong/gstreamer,ylatuya/gstreamer,ylatuya/gstreamer,mparis/gstreamer,collects/gstreamer,Distrotech/gstreamer,cfoch/gstreamer,mrchapp/gstreamer,jpakkane/gstreamer,surround-io/gstreamer,centricular/gstreamer,mparis/gstreamer,ylatuya/gstreamer,drothlis/gstreamer,magcius/gstreamer,magcius/gstreamer,lubosz/gstreamer,StreamUtils/gstreamer,centricular/gstreamer,krieger-od/gstreamer,shelsonjava/gstreamer,ensonic/gstreamer,StreamUtils/gstreamer,jpxiong/gstreamer,shelsonjava/gstreamer,cfoch/gstreamer,cablelabs/gstreamer,shelsonjava/gstreamer,ylatuya/gstreamer,mparis/gstreamer,surround-io/gstreamer,drothlis/gstreamer,jpakkane/gstreamer,ensonic/gstreamer,shelsonjava/gstreamer,jpxiong/gstreamer,collects/gstreamer,ahmedammar/platform_external_gst_gstreamer,mrchapp/gstreamer,centricular/gstreamer,Lachann/gstreamer,krichter722/gstreamer,krieger-od/gstreamer,magcius/gstreamer,cablelabs/gstreamer,justinjoy/gstreamer,magcius/gstreamer,collects/gstreamer,jpakkane/gstreamer,ahmedammar/platform_external_gst_gstreamer,mrchapp/gstreamer,Distrotech/gstreamer,surround-io/gstreamer,Lachann/gstreamer